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Simple Shell script to coordinate a cluster

In order to push configurations and binaries, start, stop, restart and purge the Ubuntu 12.04 LTS cluster this small script gets used on the FIZ cluster.

• In order to make this work without having to input passwords all the time for the sudo and ssh calls on the cluster nodes, I distributed a public ssh key on the cluster nodes for ssh auth and allowed the fcrepo user to execute sudo calls to rm, cp, service calls without a password.

• The configuration of the FIZ cluster can be accessed here: https://github.com/fasseg/fiz-fcrepo-cluster-config. There is also a setenv.sh file in there which we symlinked to $TOMCAT_HOME/bin/setenv.sh, that sets the environment variables for the repository, jgroups and infinispan configuration.
• So on each node the layout on the file system looks like this:
  • /data/fcrepo (the exploded war file, owned by fcrepo)
  • /home/fcrepo/fiz-cluster-config (the configuration and setenv.sh file, owned by fcrepo)
  • /var/lib/tomcat7/webapps/fedora (owned by root) symlinks to /data/fcrepo 
• Using this setup jar updates can be pushed by the shell script to /data/fcrepo/WEB-INF/lib directly.
• Pushing a new WAR file to the nodes requires unpacking the WAR to /data/fcrepo therefore access to /tmp is required.
• The script is setup for six nodes with know IPs. So the node[] array will have to change for different configurations, as should the range defined in the for statements in start_cluster() purge_cluster() and stop_cluster().
  
  

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